OF ARTS AND SCIENCES. 215 



■deposited, the clear liquid was decanted into another flask, and cooled 

 with ice, when crystals were formed. The same process was repeated 

 "with the mother-liquor and the residue until the whole was converted 

 into crystals ; while another crop of less pure metabrombenzylbromide 

 was obtained by adding snow to the mother-liquor from the final opera- 

 tion. The crystals were purified by similar crystallizations from hot 

 alcohol. It was necessary that all these operations should be carried 

 on in corked flasks, as the metabrombenzylbromide, when moistened 

 wnth alcohol, evaporated when exposed to the air so rapidly that there 

 was a very considerable loss from working with open vessels. 



The composition of the metabrombenzylbromide was established by 

 the following analyses : — 



0.4333 gr. substance gave after ignition with CaO 0.6609 gr. AgBr. 



Required for C-HgBro. Found. 



Carbon 33.6 " 34.63 



Hydrogen 2.4 2.G6 



Bromine 64.0 63.96 



100.0 101.25 



Properties. — Crystallized from alcohol by cooling, it forms white bladed 

 needles or plates arranged in radiated groups ; by slow evaporation of 

 its alcoholic solution, it can be obtained in flat prisms with square ends 

 sometimes reaching a length of 3 cm., and a breadth of 2 mm. It has 

 an agreeable odor, aromatic, but different fi-om that of the parabrom- 

 beuzylbromide, while its action on the mucous membrane is even 

 more violent, perhaps because it is more volatile ; its taste and action 

 on the more delicate parts of the skin is similar to that of the para 

 compound; it melts at 41°, can be distilled with steam only very 

 slowly, sublimes in oily drops, and burns with a luminous flame 

 having a green border. One of its most striking properties is that, 

 when moistened with alcohol or ether, it evaporates very rapidl}'- ; 

 whereas when dry it is comparatively fixed. It is almost insoluble in 

 water, but imparts its odor to it, is freely soluble in cold, still more so 

 in hot alcohol, and very readily soluble in ether, benzole, carbonic 

 disulphide, and glacial acetic acid. An oxidizing mixture of potassic 

 dichromate and dilute sulphuric acid seems to be without action on it ; 

 but the same mixture converts the alcohol derived from it into an acid, 

 which, in a not perfectly pure state, melts at 151° , and must therefore 

 be metabrombenzoic acid. 



o 



Ortholromhenzylhromide {C^^H^Br.CH.Br.). — After several unsuc- 

 cessful attempts to obtain an orthobromtoluol free from the para com- 



